Drive arrangement for telescopically arranged elements

ABSTRACT

The invention relates to a drive arrangement for elements telescopically received one within the other. At least three telescopic elements are required, the intermediate one functioning as a movable pulley wheel for a fixed length cable means fixedly attached at opposite ends thereof to the outer and the inner elements respectively.

United States Patent Casagrande Aug. 21, 1973 DRIVE ARRANGEMENT FOR [56]References Cited TELESCOPICALLY ARRANGED ELEMENTS UNITED STATES PATENTS[76] inventor: Bruno Casagrande, Via Zoneanard, 557,482 3/1896 Bruner eta! 175/321 33 77 1 1 3,517,760 6/1970 Kehrberger 175/321 [22] Filed:1972 Primary Examiner-Ernest R. Purser [21 A N 233,970 Attorney-RichardStevens, Richard C. Harris and Angelo J. Mele et al.

[30] Foreign Application Priority Data [57] ABSTRACT Mar. 18, 1971 ltaly83325 A/7i The invention relates to a drive arrangement for mentstelescopically received one within the other. At [52] US Cl 173/44 64/230 5 least three telescopic elements are required, the inter- [51] Int ClEzlb 17/00 mediate one functioning as a movable pulley wheel for [58]Field l} 173/43 a fixed length cable means fixedly attached at oppositeends thereof to the outer and the inner elements respectively.

5 Claims, 2 Drawing Figures DRIVE ARRANGEMENT FOR TELESCOPICALLYARRANGED ELEMENTS The present invention has, as its subject,improvements to the telescopic columns generally, but has particularutility for machines for making foundations; to be more specific,telescopic columns which operate grabs or drills and which are used inthe construction of foundations and are transported on self-propelledmeans.

Telescopic columns which are employed for this purpose are already knownand consist of two, three or more elements, the innermost element alonebeing normally driven.

These types of telescopic columns act in such a way that the motions ofdescent and/or ascent are imparted to the innermost column alone, whichduring the phase of descent draws with it all the other columns untilthey have reached the end of their run.

During the phase of ascent the innermost column rises alone until thenext column outside it strikes against its ascent buffer, after whichthey both continue the ascent together.

This system of operation has the following inconveniences:shock-absorbers are needed in the ascent buffers; discontinuous power isrequired of the lifting means and therefore adjustment of pulling forceis difficult; there is minimal guidance during descent, from when theoutermost column reaches the end of its run; construction is complex;for purposes of strength and to reach worthwhile depths it is necessaryto use a noteworthy number of columns solely for guidance purposes; soas to reach a depth of 30 meters three columns plus the guidance sleeveare required; lastly the only force exerted on the grab during the lastpart of its run is the force exerted by its own weight and by the lastcolumn.

As compared with the systems already known, the herein proposedimprovements permit the following: elemination of shock absorbers andsimplification of the construction of the columns; adjustment, asrequired and in a constant manner, both of the force to be applied tothe grab and of the speed of impact of the grab; maintenance of theguidance of the columns at an optimum value always, with a slightreduction thereof only when they are in the position of full extension;lastly, the ability to reach the same depth with fewer movable shafts,two shafts, for example being enough to reach depths of thirty meters.It can thus be seen how the improvements herein proposed enhance to anotable extent the state of the art already known.

The aforementioned improvements are embodied in the use of: drive meansplaced on a guidance sleeve which can be adjustably positioned; and alsoshafts which are subject to guidance but are self-moving, some of themacting as movable pulleys.

More particularly, the invention comprises the following, where twomovable shafts are used: a drive unit, which could even be a winch witha drum for winding up two cables in the same direction, is mountedimmovably on a guidance sleeve. While the drive means could also consistof one or two doubleaction or single-action pistons, where a winch isused as the drive means the two ends of the cables are fixed to the endsof the outer movable shaft. Thus, when one cable is slackened off, theother is wound up and viceversa, and therefor the outer movable shaftwhich slides within the guidance sleeve can be moved as required withinthat sleeve, it being enough to activate the winch; clearly, it would besufficient to use one cable connected to the base of the shaft so as tocontrol the movement of the latter, but if this were done one could onlymake use of the force of gravity and of the maximum speed which theforce of gravity is able to impart; while if two cables are used, it ispossible to drive and control the shaft as required.

As mentioned, where two movable shafts are used (although three or moremovable shafts could be employed under the mechanics of the systemproposed), the inner shaft will be connected to the guidance sleeve bytwo cables. The two cables are fixedly connected at opposite endsthereof to the guidance sleeve and to the upper end of the second (innermovable) shaft.

In the fully-raised position one cable passes over the upper end of theouter movable shaft while the second passes through the inside of thesame shaft; the first cable is then connected to the guidance sleevewhile the second turns beneath the same shaft and then also goes on tobe connected to the guidance sleeve.

Clearly, one could also have two or more drive wheels and two or morecables where I have only shown one for the sake of simplicity, just asthere could clearly be grooved pulleys or other means to prevent wear onthe cables in the areas where the cables change direction.

In the fully-raised position, therefore, the position will be that ofthe two cables which come out of the winch the one which goes upwardswill be completely unwound, while the cable which goes downwards will becompletely wound up; and of the two cables which connect the guidancesleeve to the inner movable shaft, the cable which passes above theouter movable shaft will be completely outside the same shaft, while thecable which passes below the outer movable shaft will be completelyinside the same shaft. In the fullylowered position the cables will bepositioned in the opposite manner.

With such a connecting system, the outer movable shaft functions as amovable pulley, while the cable which connects the inner shaft to theguidance sleeve performs the function of a drive cable of apredetermined fixed length. Therefore, just as with a movable pulley, ifthe length of the cable is kept fixed and the pulley wheel is moved, themoving end of the cable has to move in parameters double those of thepulley wheel, so in this invention the inner movable shaft which acts asa moving attachment moves to an extent double that of the movement ofthe outer movable shaft which acts as a movable pulley wheel.

The attached drawing shows, as an example, a preferred, non-limitativeembodiment of the invention.

FIG. 1 shows a shovel excavator, driven by cables, and illustrates atelescopic column which, in accordance with the invention comprises twomovable telescopic elements plus a guidance sleeve.

FIG. 2 is an enlarged detail view of the telescopic arrangement of FIG.1.

Referring to the drawing, reference 1 indicates an excavator, which inthis case, operates with cables but could also be of a hydraulic-drivetype or of other types normally offered commercially. The excavator 1has an arm 2, such as of the trellis type, and operates during itsmovements on the tracks 3. At the end of the arm 2, there is hinged at 4the guidance sleeve 5, to which at 6 is attached a means 7, in this casea piston, which by counteraction at 8 serves to determine the axialorientation of sleeve and, thereby of the entire telescopic column.

In place of the means 7, a cable drive could be used, in which case itsattachment point would be positioned above the point 4 if movement is tobe carried out only towards the outside of the system (i.e., movementaway from the excavator); whereas, if movement of the grab is to be bothoutwards and inwards, then two sets of cables will be attached, oneabove and the other below the point 4.

If, on the other hand, a piston or similar means are used, movement willbe carried out by means of one single counteracting means 7, whose pointof application will depend only on the availability of attachments.

Within the guidance sleeve 5 there is housed, an outer movable shaft orcolumnar element 9 within which is the inner movable shaft or columnarelement 11. The column 9 can slide axially within the guidance sleeve 5,and the column 11 can do the same within the column 9. For illustrationonly, two movable shaft elements are disclosed; however, the inventionis equally applicable to telescopic arrangements comprising more thantwo movable shafts.

The grab 10, which could be replaced with other implements, such as adrill for example, is fixed onto a platform 13 which, in turn, isconnected tothe innermost column which in this case is column 11.

The platform 13 can be immovable or rotatable. It will be rotatablewhere it is necessary to use a drill or rotating grab forexcavation-erosion work or the like.

Rotation could be provided by a hydraulic motor.

While the shafts 9 and 11 go down, the grab excavates the hole 12, whosedepth is determined by the length of the shafts.

With reference to FIG. 2, which shows, the principles of operation of atwo-movable shaft telescopic column, the guidance sleeve 5 carries onone side thereof both the drive means, such as a winch, and also thearticulated-joint means 4 and the attachment means 6, and on the otherside, in a position which is not the only one possible and has beenshown only to render the description easy, the fixture means 24 and 27,which could be replaced by one single means, for the cables 21 and 29.

Besides this, one could have on the guidance sleeve 5 some transmissionpulleys 18, 25, 26 together with others to suit the directions in whichthe cables have to run. The cables 16, 21, 29, 31 are here shown, as anexample, as being single in number, but they could be more than one innumber for each usage and could be differently positioned around theshaft.

The cables 16 and 31 extend in opposite directions from the winch 15, insuch a way that, while one is being wound up, the other is being unwoundand vice versa. By means of these cables, one can drive the telescopicshaft 9, which is fixed immovably to the cables by the fixture means 17and 19.

Correspondingly, with the cables 21 and 29, there are on the shaft 9 thetransmission pulleys 22 and 28 onto which the above said cables arepartly wound.

Said cables, which, are fixed respectively at 24 and 27 are connected tothe shaft 11, which is within the shaft 9, at 23 and, while one cable,21 to be exact, passes above the shaft 9, the other cable 29 passesbelow it.

Therefore, if the shaft 9 is lowered by an amount X, while the cables 21and 29 are connected to fixed points 24 and 27, the shaft 11 is forcedto move by an amount 2X at a speed double that at which the first shaftmoves.

If one adjusts the speed of descent or the distance to be moved on thefirst shaft 9, the driven shaft 11 will move in parameters double thoseused by the first shaft.

Thus is effected the principle of the movable pulley by using, however,a cable of fixed length which is anchored at one end to a movable means.

it is now simple for a man skilled in this field to effect telescopiccolumns of three or more movable shafts, because it is enough that themiddle of any three successive shafts should act as a movable pulley,while the outer shaft acts as a fixed point and the innermost shaft ofthe three acts as a movable point.

Under this system, the force acting on the grab or on the drill canalways be controlled and is always equal to the value desired, since theoperator determines and maintains it.

What is claimed is:

l. A telescopic column comprising at least one group of three coaxialmembers telescopically arranged one within the other, said groupcomprising an outer, an intermediate and an inner member, theintermediate one of said members being axially slidable within the outerone of said members and the inner one of said members being axiallyslidable within the intermediate one of said members, a cable meanscomprising a fixed length cable fixedly attached to the outer and innerones of said members, respectively, the intermediate one of said membersconstituting a movable pulley wheel means for said cable, whereby theinner one of said members is constrained to travel axially relative tothe outer member double the distance of the intermediate member pursuantto the intermediate member being moved axially relative to the outermember.

2. The column of claim 1, said intermediate member having a cable guideat each of two longitudinally spaced apart points thereon, said cablemeans comprising respective lengths of said cable fixedly attached tosaid inner member and extending therefrom in opposite directions to overeach of said guides and then to said outer member, said lengths of cablebeing fixed to said outer member whereby said cable lengths are constantfor all telescopic positions of said members relative to each other.

3. The column of claim 1, including a drive means for driving saidintermediate member axially relative to said outer member.

4. The column of claim 1, including a guidance means for changing theinclination of the telescopic axis relative to earth.

5. The column of claim 1 applied to an earth boring apparatus andcomprising'a boring tool attached at one end of said inner member.

i I e I l

1. A telescopic column comprising at least one group of three coaxialmemberS telescopically arranged one within the other, said groupcomprising an outer, an intermediate and an inner member, theintermediate one of said members being axially slidable within the outerone of said members and the inner one of said members being axiallyslidable within the intermediate one of said members, a cable meanscomprising a fixed length cable fixedly attached to the outer and innerones of said members, respectively, the intermediate one of said membersconstituting a movable pulley wheel means for said cable, whereby theinner one of said members is constrained to travel axially relative tothe outer member double the distance of the intermediate member pursuantto the intermediate member being moved axially relative to the outermember.
 2. The column of claim 1, said intermediate member having acable guide at each of two longitudinally spaced apart points thereon,said cable means comprising respective lengths of said cable fixedlyattached to said inner member and extending therefrom in oppositedirections to over each of said guides and then to said outer member,said lengths of cable being fixed to said outer member whereby saidcable lengths are constant for all telescopic positions of said membersrelative to each other.
 3. The column of claim 1, including a drivemeans for driving said intermediate member axially relative to saidouter member.
 4. The column of claim 1, including a guidance means forchanging the inclination of the telescopic axis relative to earth. 5.The column of claim 1 applied to an earth boring apparatus andcomprising a boring tool attached at one end of said inner member.